Travel almost anywhere in the world and you will see something so common that it may not even catch your attention. Wherever there are people, there are animals: animals being walked, herded, fed, watered, bathed, brushed or cuddled.

Many, such as dogs, cats and sheep, are domesticated, but you will also find people living alongside wild and exotic creatures such as monkeys, wolves and binturongs. Close contact with animals is not confined to one particular culture, geographic region or ethnic group. It is a universal human trait, which suggests that our desire to be with animals is deeply embedded and very ancient.

On the face of it this makes little sense. ... Since the ultimate prize in evolution is perpetuating your genes in your offspring and their offspring, caring for an individual from another species is counterproductive and detrimental to your success. Every mouthful of food you give it, every bit of energy you expend keeping it warm (or cool) and safe, is food and energy that does not go to your own kin. Even if pets offer unconditional love, friendship, physical affection and joy, that cannot explain why or how our bond with other species arose in the first place. Who would bring a ferocious predator such a wolf into their home in the hope that thousands of years later it would become a loving family pet?